Last week there was a post [1] that showed how to play YouTube without ads. I didn't want to upvote it because well, the more popular it got the more chances YouTube will figure it out and fix it. Now they fixed it.
[1]: https://news.ycombinator.com/item?id=23479435
Chances were that one Google employee passed this issue on and the YouTube team was working on a fix. Unsurprising response here.